To direct the Administrator of the Environmental Protection Agency to revise water quality criteria for ammonia, and for other purposes.

Directs the Administrator of the Environmental Protection Agency to revise and publish water quality criteria for ammonia under the Federal Water Pollution Control Act to ensure that such criteria reflect the latest and best scientific knowledge. Prohibits the Administrator, pending the issuance of such final revised criteria, from: (1) using, or requiring a State to use, water quality criteria for ammonia issued before enactment of this Act in establishing effluent limitations for ammonia; and (2) initiating or continuing, or requiring a State to initiate or continue, any enforcement action for a violation of a permit requirement based on such existing criteria.